2025-06-13
Choosing the right hub size for your bike is essential to ensuring compatibility, performance, and safety. Whether you're building a custom wheelset, replacing a damaged part, or upgrading your ride, understanding hub sizing is key. While hub selection can seem overwhelming due to the variety of options, it becomes much easier once you understand the fundamentals.
The hub is the central part of a bicycle wheel. It connects the rim to the bike frame via spokes and allows the wheel to spin smoothly thanks to internal bearings. Hub size matters because it directly affects how the wheel fits into your frame and fork, and how it performs under different riding conditions.
There are two critical dimensions to consider when talking about hub size:
Most traditional road and mountain bikes use a front hub spacing of 100mm. This has been the long-time standard and fits bikes with quick-release skewers.
Modern disc brake bikes, especially those designed for gravel, mountain, or performance road use, often adopt thru-axle systems for added stiffness and safety. Common front thru-axle sizes include:
Some vintage or specialty bikes may use less common standards like 90mm or 110mm front hubs. Always measure your existing bicycle hub or fork spacing before purchasing.
Rear hub sizing is more varied because it must accommodate the drivetrain (cassette or freewheel), braking system, and frame spacing.
These are used with quick release skewers and are becoming less common in modern high-performance bikes.
Boost and Super Boost standards increase the distance between dropouts to allow for stiffer wheels and better tire clearance.
